Circuit-controlling apparatus



Sept. 28, 1943. R. TAYLQR 2,330,759

CIRCUIT CONTROLLING APPARATUS Filed May '7, 1941 2 Sb9ets-Shee1 i.

Sept. 28, 1943. R. TAYLOR CIRCUIT CONTROLLING APPARATUS Filed May '7,1941 2 Sheets-Sheet 2 effect the yarn-selecting function.

Patented Sept. 28, 1943 CIRCUIT-CONTROLLING APPARATUS Richard Taylor,Cambridge, Mass, assignor to The Magee Carpet Company, Bloomsburg, Pa.,a corporation of Pennsylvania Application May 7, 1941, Serial No.392,400

17 Claims.

This invention relates to electrical control systems, and, moreparticularly, to a novel circuitcontrolling apparatus for making andbreaking an electrical circuit without producing objectionable arcing atswitching contacts.

The principal object of the invention is to provide a simple apparatusof this general character which may be constructed economically andwhich is highly efficient in operation.

A more specific object of the invention is to provide a novel apparatuswherein the starting and stopping of current flow in a circuit to becontrolled is effected by means of an electronic device whoseconductivity is controlled in a predetermined manner.

Another object of the invention is to provide an apparatus of the statedcharacter employing a grid-controlled rectifier tube or tubes in a novelmanner to start and stop the current flow in a circuit or circuits beingcontrolled.

A further object of the invention is to provide a novelrecord-controlled apparatus for controlling the energization of one ormore electrical devices.

The invention is particularly adapted for use in a yarn-selectingmachine having selectable electromagnets or solenoids, and, therefore, afurther object of the invention .is to provide a novel yarn-selectingmachine wherein the electromagnets are controlled without producingarcing at the magnet-selecting contacts.

Since the invention is particularly adapted to a yarn-selecting machineand in its more limited aspect relates'to the control of such a machine,it will be described with reference to this specific adaptation,although it is to be understood that the invention is not thus limitedbut is capable of general use.

In the accompanying drawings:

Fig. 1 illustrates one electromagnetically-controlled unit of ayarn-selecting machine to which the invention is applied;

Fig. 2 is a diagrammatic illustration of the electrical system employedaccording to the invention; and

Fig. 3 is an enlarged illustration of the recordcontrolledcontact-making device.

In Patent No, 2,126,634, issued to R. W. Homan on August 9, 1938, thereis fully illustrated and described a yarn-selecting machine employingelectromagnets which are selectively energized to Each margnet controlsone section of the machine. and each section comprises a plurality ofyarn carriers supported on a common track. Each time the electromagnetis energized, it operates a certain mechanism to release one of the yarncarriers, as fully described in the said patent. In its specificadaptation to such a machine, the present invention has for its objectthe provision of novel means for controlling theelectromagneticallyoperated mechanism of each section of the machine.

In Fig. 1, there is illustrated one section of a yarn-selecting machineconstructed according to the above-mentioned Homan patent with certainmodifications to adapt the machine for use with the present invention.As in the machine of the Homan patent, there are provided a plurality ofyarn-carriers I through which the yarn strands 2 loosely extend. Theyarn carriers are slidably mounted on a horizontal track comprisingstationary rods 3. The release of the yarn carriers is controlled by arotatable shaft 4 extending from a vertical plate 5 on carriage 5a whichmoves along the rods 3. Near one end of the shaft 4, there is provided apin 6 which is normally misaligned with slots in the yarn carriers. Whenthe shaft is rotated, the pin is brought into alignment with the carrierslots and one of the yarn carriers is released by virtue of the movementof carriage 5a, the remaining yarn carriers being retained due to theimmediate return of shaft 4 to its normal position. The shaft 4 isrotatable through a predetermined angle by means of a spring-biasedrack-bar l slidably carried by carriage 5a and having a gear-rackportion meshing with a pinion on the shaft. All of the above-describedmechanism is embodied in the machine of the Homan patent to whichreference may be had for a detailed disclosure.

The rack-bar l carries a pivoted latch member 8 which is normallymaintained in alignment with the rack-bar by a leaf spring 9 attached tothe bar at It). A shaft II is rotated at a constant speed and isprovided with a series of shoulders l2. When the latch member 8 is inthe normal posit-ion shown, it is out of the path of the shoulders 12,Energization of an electromagnet [3 serves to depress the latch member 8into the path of the rotating shoulders l2, whereupon one of the saidshoulders engages the shoulder Id of the latch member moving therack-bar i to the left, as viewed in Fig. 1, until the latch memher israised by its engagement with a cam member l5 mounted on plate 5. In themeantime, the electromagnet will have. been deenergized since it isenergized only for a short interval.

To effect the above-described operation, the

electromagnet has a hinged armature l6 which is 4 normally in a raisedposition. A none-magnetic separator l1 prevents the armature fromsticking to the magnet core. The armature" l6 carries an adjustable rodI 9, the lower end of which is adapted to engage the latch member 8 todepress the same against the action of spring 9 embodiment of themachine, forty-eight of such sections are employed, there being acorresponding number of electromagnets for controlling the operation.However, since the sections are superposed with respect to one another,the shaft H is common to all of them, the shoulders 12 extendingvertically throughout the entire height of the superposed sections ofthe machine. The shaft i I may be driven by the motor which actuatesother moving parts of the machine, as disclosed in the Homan patent. V

For the purpose of the present invention, it is unnecessary toillustrate in greater detail the yam-selecting machine to which theinvention is particularly adapted. The illustration of Fig. 1

is deemed suillcient for the present purpose in view of the completedisclosure of a machine of this character in the Homan patent.

' Referring now to Fig. 2, there is illustrated the novelcircuit-controlling means provided by this invention which is adapted tocontrol the energization of the electromagnets in a machine of thecharacter above described, but which is also capable of general use forcontrolling the energization of one or more electrical devices. Thewindings of the electromagnets, which in this instance are the devicesto be energized, are represented at 22. Only two of the windings areshown in full, the arrowhead connections 23 representlng connections toother electromagnets. Of course, there may be any number of theelectromagnets, as previously mentioned. A common conductor 24 serves asone of the currentsupply connections to the electromagnets. theindividual connections to the magnet windin s being connected inparallel to the conductor 24. A second common current-supply connect onfor the electromagnet windings is shown at 25. One end of conductor 25is connected to a ground point 26, while the opposite end iselectrically connected to a metal roll 21. The c nnection to the roll isdiagrammatically illustrated. but it will be understood that thisconnection may be of any suitable type. For example, it may comprise abrush engaging the rotatable roll. Contact fin gers or brushes 28, towhich the respective magnet windings are connected, en age the clindrical surface of the metal roll 21. The currentsupply connections tothe magnet wind ngs are selectably completed by means of a pattern orrecord which may take the form of a perforated insulating sheet, asdescribed in the above-mentioned patent. In Fig. 3, there is an enlargedshowing of the contact-making roll 27 over which the record or patternsheet 29 passes. The roll 2i is rotated at a predetermined speed, forexample, by means of a m'otor employed in the machine, as described inthe Homan patent. The

perforations in the record or pattern sheet are equally spacedlongitudinally of the sheet, and these holes are of a predetermined sizeso that the current-supply connections for the electromagnets areselectively energized during successive intervals'of very shortduration.

In accordance with the present invention, the selective energization ofthe electromagnet windings is effected by means of the apparatus now tobe described without making or breaking the current-supply connectionswhile current is flowing therein. The current input conductors 30 arerepresentative of any suitable current-supply source, and in thespecific apparatus illustrated, these conductors are assumed to beconnected to an alternating current source, for example, the usualcommercial source of sixty cycle current of suitable voltage, such asvolts. A fullwave rectifier comprising transformer 3| and electrondischarge tubes 32 and 33 is adapted to supply unidirectional current tothe electromagnet windings. As is usual in this type of rectifier, thetransformer 3| has two secondary windings 34 and 35, and the filamentsof the tubes are connected across the low voltage winding 34, while thetube anodes are connected to opposite terminals of the relatively highvoltage winding 35. As is also customary, each of the secondary windingsis center-tapped and the rectified current output is derived from theleads 24 and 36 connected to the center taps of the said windings. Itwill be noted that the conductor 36 is connected to the grounded point26. It will be understood that the tubes 32 and 33 are adapted tooperate on alternate half cycles of the alternating current.

The-tubes 32 and 33 are grid-controlled rectifier tubes and these tubesare preferably thyratrons of the type known as 2A4G. Such a tube ischaracterized in that current will flow between its anode and cathodewhen the grid voltage is zero with respect to the cathode. Therefore, toprevent anode-to-cathode conduction, the grid must be made negative withrespect to the oathode during the time that the anode is at a positivepotential. In the circuit illustrated, the tubes are renderednormally-non-conductive by connecting the grid of each tube to the anodeof the other tube through a suitable current-limiting resistor 31 or 38.Condensers 39 and 40 are also provided in these connections for apurpose which will be explained presently.

Disregarding the condensers 39 and 40 for the moment, it will be seenthat during one-half cycle of the alternating current, the anode of tube32 will be positively charged, while the anode of tube 33 is negativelycharged. At such time, therefore, the tube 32 is conditioned foranodeto-cathode conduction, but the grid of the tube is negativelybiased by virtue of its connection to the terminal of secondary winding35 opposite the terminal to which the anode is connected. Therefore, thetube is rendered nonconductive. During the other half cycle of thesupply current, tube 33 is conditioned for anodeto-cathode conduction,but its grid is negatively biased in a similar manner.

The tubes 32 and 33 are rendered conductive at predetermined times bymeans of the contact roller M which serves to reduce the potential ofthe grid of each tube substantially to zero with respect to the cathode.To this end, the roller 3| is formed of metal, and it has an insulatingsection 42 which may cover one-half of the cylindrical surface of theroller. The grids of the tubes are connected by means of conductors 43and 44 to contact brushes 45 and 46 engaging the cylindrical surface ofthe roller. The metallic portion of the roller is connected to thegrounded point 28 by means of conductor 41. It will be seen, therefore,that as the roller 4| rotates, the grids of tubes 32 and 33 areconnected intermittently to the tube cathodes when the brushes 45 and 43engage the conductive portion of roller 4|. This connection of the gridsto their respective cathodes is via the conductors 43 and 44, theconductive portion of the roller 4|, conductors 41 and 36, and thesecondary winding 34. The voltage across Winding 34 may be disregardedin this instance.

The roller 4| is rotated in coordination with the roller 21 and theperforated sheet 29 so that the tubes 32 and 33 are rendered conductivewithin the time intervals during which the connections to theelectromagnets are completed.

. The roller 4| -should be so designed and should be rotated at. apredetermined speed such that the brushes 45 and 46 engage theconductive portion of the roller after contact has been made with one ofthe brushes 28 through a perforation in the record sheet 29, and thebrushes 45 and 46 leave the conductive portion of roller 4| before thecontact is interrupted at the brush 28. The roller 4| may be properlycoordinated with roller 21 by suitable gearing 48 and the two rollersmay be driven from the same source of power.

Thus, it will be seen that the current-supply connections to theelectromagnet windings 22 are not made or broken while current isflowing in such connections, the current flow being started after aconnection is made and being stopped before a connection is broken,through the action of the contact roller 4| which functions to start andstop the rectifier tubes 32 and 33. In this manner, pitting and burningof the contacts at the roller 21 is prevented. Since the load circuitcomprising the electromagnet \vindngs is an inductive D. C. circuit,serious pitting and burning of the contacts would result from theopening and closing of the circuit under load. This has been a seriousdefect of prior devices of this character. By the present invention,this defect is eliminated.

It is important to note that the contact roller 4| is only required tohandle very small currents in non-inductive circuits, and, therefore, nopitting or burning will take place. Moreover, the resistors 31 and 38serve to limit the current to contact roller 4|-, as well as to thegrids of the tubes.

If the load devices supplied by the rectifier tubes were entirelynon-inductive, it would be unnecessary to use the condensers 39 and 40.However, the load devices are inductive and the presence of theirinductance in the load circuit tends to disturb the phase relationbetween the grid and anode voltages of the rectifier tubes. As a result,the anodes tend to swing positive before the negative voltage on the grds has become large enough to prevent conduction. The condensers 39 and40 prevent this condition from obtaining. Since the grid of each tubegoes positive when its anode is negative, grid rectification takes placein the tube and the associated condenser is charged by grid currentflowing through the resistance 31 or 38 and the grid-cathode path withinthe tube. The voltage which is thus produced across each condenser is insuch a direction as to increase the normal negative A. C, bias on thegrids. Thus, there is provided a novel means utilizing gridrectification action of the tubes to provide a negative D. C. bias onthe grids during the intervals when the tubes are not renderedconductive by the contact roller 4|.

In one physical embodiment of the invention which was found to operatesatisfactorily, the electrical elements were as follows:

Tubes 32 and 33 were of the type above mentioned.

The transformer 3| was adapted for volts on its primary and produced 220volts across secondary 35 and 2.4 volts across secondary 34.

Theresistors 31 and 38 were 1,000 ohm, 5 watt, wire-wound resistors.

The condensers 39 and 40 were of th paper tubular type, each having acapacitance of 0.01 microfarad.

From the above description, it will be seen that the invention providesa novel apparatus for controlling the energization of one or moreelectrical devices without making and breaking the connections to suchdevices while current-is flowing therein. Obviously, the invention isnot limited to the specific form illustrated. The contact making roller21 and the associated record sheet are representative of any device forcompleting the connections. to an electrical device during apredetermined interval. Obviously, this function may be performed byother specific forms of contact-making devices. For example, theconnections to a device to be energized during a predetermined intervalor during recurring intervals could be operated by means of acam-actuated switch. such as is commonly employed in electrical devices.Regardless of the nature of the mechanism for completing the connectionsto the device or devices to be energized, the contact roller 4| may becoordinated with such mechanism so as to effect starting and stopping ofthe current flow within the interval during which the connections aremade.

It will be apparent also that the invent on is capable of use in a widevariety of elec rical devices. For example, it may be employed inconnection with sign lighting where it is desired to operate one or morecircuits intermittently. Hence, the electromagnet windings 22 are to beconsidered as representative of any electrical device or devices to beenergized during a predetermined nterval or intervals.

It will be understood, therefore, that the invention is not limited tothe specific disclosure, but is capable of various modifications withinthe scope of the appended claims.

I claim:

1. In a circuit controlling apparatus, an electrical device whoseenergization it is desired to control, current supply connections forsaid device, contact making means for completing said connections duringa predetermined interval, a source of alternating current, rectifyingmeans including a grid-controlled rectifier tube for en ergizing saiddevice from said source via said connections, means for applying anegative biasing potential to the grid of said rectifier tube of amagnitude to render the tube normally non-conducting, and means forrendering said tube conductive after the commencement of said intervaland for permitting said biasing potential to become effective before thetermination of said interval, whereby said deviceis energized withoutmaking or breaking said connections while current is flowing therein.

2. In a circuit controlling apparatus, an electrical device whoseenergizaton it is desired to control, current supply connections forsaid device, contact making means for completing said connections duringa predetermined interval, a source of energizing current, meansincluding a grid-controlled electron discharge tub for supplying currentfrom said source to said device, means for causing the grid of said tubeto draw current, means responsive to the grid current flow for biasingthe gridof said tube so as to render it non-conductive, and means forrendering said tube conductive after the commencement of said intervaland for permitting the grid bias to become efiective before thetermination of said interval, whereby said device is energized withoutmaking or breaking said connections While current is flowing therein.

3. In a circuit controlling apparatus, an electrical device whoseenergization it is desired to control, current supply connections forsaid device, contact making means for completing said connections duringrecurring intervals, a source of alternating current, a full-waverectifier for supplying current to said connections, said rectifierincluding a pair of grid-controlled rectifier tubes arranged to operateon alternate half cycles of the alternating current from said source,and means for rendering said tubes operative after the commencement ofeach said interval and for rendering said tubes inoperative -before thetermination of each interval, whereby said device is energizedrecurrently without making or breaking said connections while current isflowing therein.

4. In a circuit controlling apparatus, an electrical device whoseenergization it is desired to control, current supply connections forsaid de vice, record-controlled contact making means for completing saidconnections during recurring intervals, a source of alternating current,a fullwave rectifierfor supplying current to said connections, saidrectifier including a pair of gridcontrolled rectifier tubes arranged tooperate on alternate half cycles of the alternating current from saidsource, and means operable coordinately with said record-controlledmeans for varying the grid potential of said tubes so as to render thetubes operative after the commencement of each said interval and torender the tubes inoperative before the termination of each interval,whereby said device is energized recurrently without making or breakingsaid connections while current is flowing therein.

5. In a circuit controlling apparatus, an electrical device whose energzation it is desired to control, current supply connections for saiddevice, record-controlled contact making means for completing saidconnections during recurring intervals, a source of alternating current,a fullwave rectifier for supplying current to said connections, saidrectifier including a pair of gridcontrolled rectifier tubes arranged tooperate on alternate half cycles of the alternating current from saidsource, means for causing the grids of said tubes to draw current, meansresponsive to the grid current for biasing the grids of the tubes so asto render them non-conductive, and means for rendering said tubeconductive after the commencement of each said interval and forpermitting the grid bias to become efiective before the termination ofeach interval, whereby said device is energized recurrently withoutmaking or breaking said connections while current is flowing therein.

6. In a circuit-controlling apparatus, an electrical device whoseenergization it is desired to control, current-supply connections forsaid device, record-controlled contact-making means for completing saidconnections during recurring intervals, a source of alternating current,a fullwave rectifier for supplying current to said connections, saidrectifier including a transformer and a pair of grid-controlledrectifier tubes connected to said transformer so as to operate onalternate half cycles of the alternating current from said source, saidtransformer including a secondary windingand said tubes having theiranode elements connected to opposite terminals of said secondarywinding, a condenser connected between the grid of one tube and theterminal of said winding opposite the terminal to which the anode ofsaid tube is connected, a second condenser connected between the grid ofthe other tube and the terminal of said winding opposite the terminal towhich the anodeof said other tube is connected, whereby said tubes arerendered non-conductive by biasing voltages established across saidcondensers due to grid rectification in the tubes, and means fornullifying the efiect of said biasing voltages to render said tubesconductive after the commencement of each said interval and forpermitting the biasing voltages to become effective before thetermination of each interval, whereby said device is energizedrecurrently without making or breaking said current-supply connectionswhile current is flowing therein.

7. In a circuit-controlling apparatus, a plurality of electrical devicesto be selectively energized, current-supply connections for saiddevices, record-controlled contact-making means for selectivelycompleting connections to said devices during successive intervals, asource of alternating current, a full-wave rectifier for supplyingcurrent to said connections, said rectifier including a transformer anda pair of grid-controlled rectifier tubes connected to said transformerso as to operate on alternate half cycles of the alternating currentfrom said source, said transformer including a secondary winding andsaid tubes having their anode elements connected to opposite terminalsof said secondary winding, a condenser connected between the grid of onetube and the terminal of said winding opposite the terminal to which theanode of said tube is connected, a second condenser connected betweenthe grid of the other tube and the terminal of said winding opposite theterminal to which the anode of said other tube is connected, wherebysaid tubes are rendered non-conductive by biasing voltages establishedacross said condensers due to grid rectification in the tubes, and meansfor nullifying the effect of said biasing voltages to render said tubesconductive after the commencement of each said interval and forpermitting the biasing voltages to become effective before thetermination of each interval, whereby said devices are selectivelyenergized without making or breaking said current-supply connectionswhile current is flowing therein.

8. In a yarn-selecting apparatus, a plurality of electromagnets,connections for supplying current to said electromagnets,record-controlled means for selectively completing said connectionsduring predetermined intervals, a source of alternating current,rectifier means including a grid-controlled rectifier'tube for supplyincurrent from said source to said electromagnets, and means for renderingsaid tube conductive after the commencement of each said interval andfor rendering said tube non-conductive before the termination of eachinterval, whereby said electromagnets are selectively energized withoutmaking or breaking said connections while current is flowing therein.

9. In a yarn-selecting apparatus, a plurality of electromagnets,connections for supplying current to said electromagnets,record-controlled means for selectively completing said connections.during predetermined intervals, a source of al- 'ment of eachsaid'interval and to render the 7 -tubes inoperative before thetermination of each interval, whereby said electromagnetsa'reselectively energized without making or breaking said connectionswhile current is flowing therein.

10. In an. electrical system, a source-of alternating current supply, aload circuit to besupplied therefrom, a. grid-controlled rectifier tubeserially connected in said load circuit, means normally biasing the gridof said tube so as to render the tube non-conductive, contact-makingmeans in said load circuit, means for closing said contact-making meansduring a predetermined interval, and means operable coordinately withsaid contact-making mcans for varying the bias on the grid of said tubeso as to render the tube conductive after the commencement of saidinterval and to render the'tube non-conductive before the termination ofsaid interval, whereby the load circuit is energized without making orbreaking the load circuit connections while current is flowing therein.

11. In a circuit controlling apparatus, an electrical device whoseenergization it is desired to control, current supply connections forsaid device, contact making means for completing said connections duringa predetermined interval, a source of alternating current, rectifyingmeans including a grid-controlled rectifier tube for supplying currentto said connections, and means for rendering said tube operative afterthe commencement of s id interval and for rendering said tube inoper%ivebefore the termination of Said interval, wh reby said device isenergized without making or breaking said connections while current isflowing therein.

12. In a circuit controlling apparatus, a plurality of electricaldevices to be selectively en-' ergized, current supply connections forsaid de vices, contact making means for selectively completingconnections to said devices during successive intervals, a source ofalternating current, rectifying means including a grid-controlledrectifier tube for supplying current to said connections, and means forrendering said tube operative after the commencement of each saidinterval and for rendering said tube inoperative before the terminationof each interval, whereby said devices are selectively energized withoutmaking or breaking said connections while current is flowing therein.

13. In a yarn-selecting apparatus, a source of alternating currentsupply, a load circuit to be supplied therefrom, said load circuitinclud ing a plurality of parallel branches, a plurality ofelectromagnets connected respectively in said parallel branches forenergization from said source, a grid-controlled rectifier tube seriallyconnected in said load circuit for supplying current from said source tosaid electromagnets, contact-making means for selectively closing saidparallel branches during predetermined intervals, and means forrendering said tube conductive after the commencement of each intervaland for rendering said tube non-con- 5 ductive before the termination ofeach interval,

' whereby said electromagnets are selectively energized without makingor breaking the load circuit connections while current is flowingtherein.

14. In an electrical system, a source of alter- .nating current supply,a load circuit to be supplied therefrom, rectifying means including agrid-controlled rectifier tube serially connected in said load circuitfor supplying current thereto, contact-making means for closing saidload circuit during a predetermined interval, and means for renderingsaid tube operative after the commencement of said interval and forrendering said tube inoperative before the termination of said interval,whereby the load circuit is energized without making or breaking theload circuit connections while current is flowing therein.

15. In an electrical system, a source of alternating current supply, aload circuit to be supplied therefrom, said load circuit including aplurality of parallel branches, a plurality of electrical devicesconnected respectively in said parallel branches for energization fromsaid source, rectifying means including a grid-controlled rectifier tubeserially connected in said load circuit for supplying current thereto,contact-making means for selectively closing said parallel branchesduring successive intervals, and means for rendering said tube operativeafter the commencement of each interval and for rendering said tubeinoperative before the termination of each interval, whereby saiddevices areselectively energized without making or breaking the loadcircuit connections while current is flowing therein.

16. In an electrical system, a source of alternating current supply, aload circuit to be supplied therefrom, a full-wave rectifier seriallyconnected in said load circuit, said rectifier including a pair ofgrid-controlled rectifier tubes arranged to operate on alternate halfcycles of the alternating current from said source, contactmaking meansfor closing said load circuit during a predetermined interval, and meansfor rendering said tubes operative after the commencement of saidinterval and for rendering said tubes inoperative before the terminationof said interval, whereby the load circuit is energized without makingor breaking the load circuit connections While current is flowing there-17. In an electrical system, a source of alternating current supply, aload circuit to be supplied therefrom, rectifying means including agrid-controlled rectifier tube serially connected in said load circuitfor supplying current thereto, means for causing the grid of said tubeto draw current, means responsive to the grid current for biasing thegrid of said tube so as to render the tube non-conductive,contact-making means for closing said load circuit during apredetermined'interval, and means for rendering said tube conductiveafter the commencement of 70 said interval and for permitting the gridbias to become effective before the termination of said interval,whereby the load circuit is energized without making or breaking theload circuit connections while current is flowing therein.

RICHARD TAYLOR.

